Link systems and articulation mechanisms for remote manipulation of surgical or diagnostic tools

ABSTRACT

Articulating mechanisms, link systems, and components thereof, useful for a variety of purposes including, but not limited to, the remote manipulation of instruments such as surgical or diagnostic instruments or tools are provided. The link systems include links wherein at least two adjacent links are pivotable relative to one another around two distinct pivot points. Mechanisms for locking the links are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of application Ser. No. 10/928,479,entitled, LINK SYSTEMS AND ARTICULATION MECHANISMS FOR REMOTEMANIPULATION OF SURGICAL OF DIAGNOSTIC TOOLS, filed Aug. 26, 2004 whichclaims priority to Application No. 60/577,757, entitled, ARTICULATINGMECHANISM WITH FLEX-HINGED LINKS, filed Jun. 7, 2004, the contents ofwhich are hereby incorporated by reference into the present disclosure.

FIELD OF THE INVENTION

This invention relates to link systems and applications thereof,including the remote guidance and manipulation of surgical or diagnosticinstruments and tools.

BACKGROUND OF THE INVENTION

The ability to easily remotely steer, guide and/or manipulateinstruments and tools is of interest in a wide variety of industries andapplications, in particular where it is desired to navigate aninstrument or tool into a workspace that is not easy to manuallynavigate by hand or that might otherwise present a risk or danger. Thesecan include situations where the targeted site for the application of atool or instrument is difficult to access, e.g. certain surgicalprocedures, or the manufacture or repair of machinery, or evencommercial and household uses, where manual access to a targeted site isrestricted or otherwise. Other situations can include e.g. industrialapplications where the work environment is dangerous to the user, forexample, workspaces exposed to dangerous chemicals. Still othersituations can include e.g. law enforcement or military applicationswhere the user may be at risk, such as deployment of a tool orinstrument into a dangerous or hostile location.

Using surgical procedures as an illustrative example, procedures such asendoscopy and laparoscopy typically employ instruments that are steeredwithin or towards a target organ or tissue from a position outside thebody. Examples of endoscopic procedures include sigmoidoscopy,colonoscopy, esophagogastroduodenoscopy, and bronchoscopy.Traditionally, the insertion tube of an endoscope is advanced by pushingit forward, and retracted by pulling it back. The tip of the tube may bedirected by twisting and general up/down and left/right movements.Oftentimes, this limited range of motion makes it difficult to negotiateacute angles (e.g., in the rectosigmoid colon), creating patientdiscomfort and increasing the risk of trauma to surrounding tissues.Laparoscopy involves the placement of trocar ports according toanatomical landmarks. The number of ports usually varies with theintended procedure and number of instruments required to obtainsatisfactory tissue mobilization and exposure of the operative field.Although there are many benefits of laparoscopic surgery, e.g., lesspostoperative pain, early mobilization, and decreased adhesionformation, it is often difficult to achieve optimal retraction of organsand maneuverability of conventional instruments through laparoscopicports. In some cases, these deficiencies may lead to increased operativetime or imprecise placement of components such as staples and sutures.Steerable catheters are also well known for both diagnostic andtherapeutic applications. Similar to endoscopes, such catheters includetips that can be directed in generally limited ranges of motion tonavigate a patient's vasculature.

There have been many attempts to design endoscopes and catheters withimproved steerability. For example, U.S. Pat. No. 3,557,780 to Sato;U.S. Pat. No. 5,271,381 to Ailinger et al.; U.S. Pat. No. 5,916,146 toAlotta et al.; and U.S. Pat. No. 6,270,453 to Sakai describe endoscopicinstruments with one or more flexible portions that may be bent byactuation of a single set of wires. The wires are actuated from theproximal end of the instrument by rotating pinions (Sato), manipulatingknobs (Ailinger et al.), a steerable arm (Alotta et al.), or by a pulleymechanism (Sato). U.S. Pat. No. 5,916,147 to Boury et al. discloses asteerable catheter having four wires that run within the catheter wall.Each wire terminates at a different part of the catheter. The proximalend of the wires extend loosely from the catheter so that the physicianmay pull them. The physician is able to shape and thereby steer thecatheter by selectively placing the wires under tension.

Although each of the devices described above are remotely steerable,their range of motion is generally limited. The steering mechanisms mayalso be laborious to use, such as in the catheter of Boury et al. whereeach wire must be separately pulled to shape the catheter. Further, inthe case of e.g. endoscopes and steerable catheters that use knob andpulley mechanisms, it requires a significant amount of training tobecome proficient in maneuvering the device through a patient's anatomy.

Consequently, a device with enhanced remote maneuverability tocontrollably navigate complex geometries may allow more efficient andprecise advancement and deployment of instruments and tools. It wouldalso be advantageous for such a device to provide a more intuitive andfacile user interface to achieve such enhanced maneuverability. It wouldbe further advantageous for such a device to limit undesired tension orslack in cable components. In addition, it would be advantageous forsuch a device to have a locking mechanism capable of preventing movementof the device. Such a device would have widespread application inguiding, steering and/or manipulating instruments and tools acrossnumerous industries. Such a device would also of itself haveentertainment, recreation and educational value.

SUMMARY OF THE INVENTION

The present invention provides for articulating mechanisms, linksystems, and components thereof, useful for a variety of purposesincluding, but not limited to, the remote manipulation of instrumentssuch as surgical or diagnostic instruments or tools. Such instrumentsand tools can include surgical or diagnostic instruments or tools,including but not limited to endoscopes, catheters, Doppler flow meters,microphones, probes, retractors, dissectors, staplers, clamps, graspers,scissors or cutters, ablation or cauterizing elements, and the like.Other instruments or tools in non-surgical applications include but arenot limited to graspers, drivers, power tools, welders, magnets, opticallenses and viewers, electrical tools, audio/visual tools, lasers,monitors, and the like. Depending on the application, it is contemplatedthat the articulating mechanisms, link systems, and other components ofthe present invention can be readily scaled to accommodate theincorporation of or adaptation to numerous instruments and tools. Thelink systems and articulating mechanism may be used to steer theseinstruments or tools to a desired target site, and can further beemployed to actuate or facilitate actuation of such instruments andtools.

In one aspect of the invention, a link system is provided that includesa plurality of links, wherein at least two adjacent links are pivotablerelative to one another about two distinct pivot points. In certainvariations the adjacent links have opposing surfaces with each surfacehaving an axially aligned convex protrusion or concave depression. Insuch variations, the link system further includes a bushing interposedbetween at least two adjacent links, the bushing contacting the convexprotrusion or concave depression of each of the at least two adjacentlinks. The bushing may include a concave depression or convex protrusionconfigured to receive an opposing convex protrusion and/or concavedepression of the adjacent links. In some instances, the convexprotrusion or concave depression of adjacent links is hemispherical.Such link systems can be incorporated into or otherwise form componentsof articulating mechanisms according to the invention.

In another aspect of the invention, an articulating mechanism isprovided for, e.g., remote manipulation of a surgical or diagnostictool. The articulating mechanism can include one or more link systemsthat allow for remote manipulation of a distally located tool orinstrument. In one variation, an articulating mechanism is provided thatincludes multiple pairs of links, each link being maintained in a spacedapart relationship relative to the other link of the pair. At least twoadjacent links are pivotable relative to one another about two distinctpivot points. In certain variations the adjacent links have opposingsurfaces each have an axially aligned convex protrusion or concavedepression, and are separated by a bushing interposed therebetween. Thearticulating mechanism further includes multiple sets of cables, eachset connecting the links of a discrete pair to one another such thatmovement of one link of a pair causes corresponding relative movement ofthe other link of the pair. In certain variations, the links aredesigned to reduce or eliminate excess cable slack or tension betweenadjacent links.

In a further aspect of the invention, a locking mechanism is providedthat may be incorporated into an articulating mechanism. The mechanismis configured to receive one or more cables (or other actuatingelements) distally connected to one or more links and, when activated,impede movement of the cables (or other actuating elements) thusimpeding movement of the corresponding links themselves. In oneembodiment of the locking mechanism, the mechanism is configured suchthat each cable is able to pass between a moveable locking member and afixed contact member. Movement of the moveable locking member causes oneor more cables to contact the fixed contact member thereby frictionallyimpeding the movement of one or more cables.

In another embodiment, the locking mechanism can include one or morelocking channels positioned perpendicular to the central axis of thelocking mechanism. A moveable button member is positioned in each of theone or more locking channels within the mechanism housing. The housingcan include one or more through-channels that receive one or more cables(or other actuating elements), with each locking channel associated witheach through-channel. Depression of the button member within the lockingchannel brings a cable (or other actuation elements) in an associatedthrough-channel into frictional contact with the cylinder, therebyfrictionally impeding movement of the cable.

In another embodiment, the locking mechanism includes a dual collarmechanism having axially aligned fixed and moveable collars. One or morecable sets (or other actuation elements) pass through one collar andaround the perimeter of the other collar. Axial movement of the moveablecollar towards the fixed collar brings the cables into contact with bothcollars, thereby frictionally impeding movement of the cables.

In a further aspect of the invention, a surgical device is provided thatincludes a surgical or diagnostic tool and a plurality of links proximalof the surgical or diagnostic tool. An elongate shaft is proximal of theplurality of links, and one or more cables are distally connected to oneor more links and received proximally through the elongate shaft.Movement of one or more cables causes movement of one or more links.Again, at least two adjacent links are pivotable relative to one anotherabout two distinct pivot points. In certain variations, at least two ofthe adjacent links have opposing surfaces with an axially aligned convexprotrusion and/or concave depression and are separated by a bushinginterposed therebetween. The bushing contacts the convex protrusion orconcave depression of each of the adjacent links.

In further aspects of the invention, a tool or instrument may beattached to and extend from the link systems and/or articulatingmechanisms, or the link systems and/or articulating mechanisms may beotherwise incorporated into such instruments or tools. In the case ofsurgical applications, examples of surgical or diagnostic tools include,but are not limited to, endoscopes, catheters, Doppler flow meters,microphones, probes, retractors, dissectors, staplers, clamps, graspers,scissors or cutters, and ablation or cauterizing elements. For otherapplications, numerous tools or instruments are likewise contemplated,including without limitation, e.g., graspers, drivers, power tools,welders, magnets, optical lenses and viewers, light sources, electricaltools, audio/visual tools, lasers, monitors, and the like. The types oftools or instruments, methods and locations of attachment, andapplications and uses include, but are not limited to, those describedin pending and commonly owned U.S. application Ser. No. 10/444,769,incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a perspective view of a surgical needle driver deviceaccording to one embodiment of the invention, with proximal and distalarticulating link systems;

FIG. 1B shows a top view of the embodiment of FIG. 1A, with the devicearticulated into a different position;

FIG. 2A shows an expanded perspective view of a link system similar tothe distal link system of the embodiment depicted in FIG. 1A, withadjacent links that include opposing axially aligned convex protrusionsseparated by a bushing interposed between the convex protrusions;

FIG. 2B shows a side view of the link system of FIG. 2A;

FIG. 2C shows a cross-sectional view of the link system shown in FIG.2A, taken along the plane designated by line K-K;

FIG. 2D shows a side view of the link system of FIG. 2A in a bentconfiguration;

FIGS. 2E and 2F show straight and bent sectional views respectively, ofa link system similar to that of FIG. 2A;

FIG. 3A shows an expanded side view of the device depicted in FIG. 1with parts broken away;

FIG. 3B shows an expanded cross-sectional view of the device depicted inFIG. 1 with parts broken away;

FIG. 4 shows a detailed cross-sectional view of the distal end tool andlink assembly of the device depicted in FIG. 3B, designated by area A;

FIG. 5 shows a detailed cross-sectional view of the proximal link-handleassembly of the embodiment depicted in FIG. 3B, designated by area B;

FIGS. 6A and 6B show straight and bent sectional views, respectively, ofa link system according to another embodiment depicted in the invention,with adjacent links including opposing axially aligned concave socketsseparated by a bushing interposed between the concave sockets;

FIGS. 7A and 7B show straight and bent sectional views, respectively, ofa link system according to yet another embodiment of the invention;

FIG. 8 shows a perspective view of a surgical needle driver instrumentaccording to another embodiment of the invention, with the location ofthe distal links varied;

FIGS. 9A and 9B show a side view of a link locking mechanism accordingto another embodiment of the invention, in locked (9A) and unlocked (9B)positions, respectively;

FIG. 10A shows a top view of the locking mechanism of FIG. 9A;

FIGS. 11A and 11B show sectional views of the locking mechanism of FIG.9A;

FIGS. 12A and 12B show expanded cross-sectional views of the lockingmechanism of FIGS. 9A and 9B, designated by areas C and D, respectively;

FIG. 13 shows a perspective view of a locking mechanism, according toanother embodiment of the invention;

FIG. 14 shows a side view of the locking mechanism of FIG. 13;

FIG. 15 shows a top view of the locking mechanism of FIG. 13;

FIG. 16 shows an end view of the locking mechanism of FIG. 13;

FIGS. 17A-17C show top views of the locking mechanism of FIG. 13, inunlocked (FIG. 17A) partially locked, (FIG. 17B) and locked positions(FIG. 17C);

FIGS. 18A-18C show cross-sectional views of the locking mechanismdepicted in FIG. 17A-C, respectively, taken along planes designated bylines 18A-18A, 18B-18B, and 18C-18C, respectively;

FIG. 19 shows a perspective view of a link locking mechanism, accordingto yet another embodiment depicted in the invention;

FIGS. 20A and 20B show cross-sectional views taken perpendicular to thelongitudinal axis of the mechanism of FIG. 19 in locked (20B) andunlocked (20A) conformations, respectively; and

FIGS. 21A and 21B show straight and bent sectional views, respectively,of a link system according to another embodiment of the invention,configured for neutral cable bias;

FIGS. 22A and 22B show straight and bent sectional views, respectively,of a link system according to yet another embodiment of the invention,configured for negative cable bias; and

FIGS. 23A and 23B show straight and bent sectional views, respectively,of a link system according to a further embodiment of the invention,configured for positive cable bias.

DETAILED DESCRIPTION OF THE INVENTION

As further detailed herein, articulating link systems and mechanisms areprovided that can form, or be incorporated into, or otherwise constitutea wide variety of devices. The link systems may be made from acombination of individual links. Articulating mechanisms according tothe invention generally include multiple pairs of links and at least oneset of cables connecting at least one discrete pair of links. The term“link” as used herein refers to a discrete portion of a link system orarticulating mechanism that is capable of movement relative to anotherdiscrete portion of the mechanism or system. In some embodiments, thelink may correspond to another discrete portion or defined area at theopposite end of the mechanism. Links are typically, but need not be,cylindrical. The links are generally aligned along the longitudinal axisof the mechanism. In certain embodiments, the link systems will includea plurality of links, at least two of which are separated by a bushing.

The link systems can form or be incorporated into a variety ofarticulating mechanisms. In various embodiments, articulating mechanismsaccording to the invention generally include multiple pairs of links andmultiple sets of cables. In further embodiments, the articulatingmechanism includes a plurality of links or segments that are members ofdiscrete pairs. The links form a proximal end and a distal end, with onelink of each pair being situated in a link system at the proximal end,and the other link of the link pair in a link system at the distal end.

In such articulating mechanisms, each cable set connects the links of adiscrete pair in the articulating mechanism to one another so thatmovement of one link of a pair causes a corresponding movement of theother link in the pair. As used herein, the term “active link” or“active link pair” refers to links that are directly connected to oneanother by a cable set. The term “spacer link” or “spacer link pair”refers to links that are not directly connected by a cable set. Spacerlinks can nevertheless be disposed between active links and provide forthe passage of cable sets that connect active link. The ability tomanipulate active link pairs allows for the mechanism to readily formcomplex three-dimensional configurations and geometries as is furtherdetailed herein. With conventional articulating devices that rely oncable sets or wires that pass through otherwise unconnected links, it isdifficult to obtain such complex geometries because such devices aretypically designed such that the steering cables or wires pass througheach link and terminate at a distal-most link. Thus, all the segmentsbend together in a coordinated response to movement of the wire or cableset, typically in a curved, or arcuate fashion.

The link systems or articulating mechanisms of the present inventionmay, for example, be incorporated into devices used to direct and steera surgical or diagnostic instrument tool to a target site within a bodyregion of a patient. The device can be introduced either in its native,straight configuration, or after undergoing various manipulations at itsproximal end from a location outside the patient. In variousembodiments, link systems form a part or parts of an articulatingmechanism. Movement of the proximal end of the mechanism, results inmovement at the distal end. Further, the resulting directional movementof the distal end can be inverted, mirrored or otherwise, depending onthe degree of rotation of the proximal end relative to the distal end.Also, the proximal end provides for a user interface to control thesteering and manipulation of the distal end that is convenient and easyto use. This user interface allows for example a user to readilyvisualize the shape and directional movement of distal end of themechanism that is located e.g. within a patient based on the manipulatedshape of the externally positioned proximal end user interface.Alternatively, control or actuation of the distal end links can beaccomplished by more conventional methods of manipulating the linkactuating cables, e.g., through the use of knob and pulley systems andthe like.

In addition to the formation of complex configurations, the presentinvention also allows for increased rigidity of the mechanism byconstraining manipulated active links and allowing such links to resistmovement due to laterally applied forces. A given link pair isconsidered fully constrained if upon manipulating the links to achievethe desired shape, and fixing one link of the pair in that desiredshape, the other link of the pair can resist loads while maintaining itsdesired, unloaded shape. For links that are otherwise free to move inthree degrees of freedom, a minimum of three cables are required tofully constrain the links. This is not always the case with conventionalarticulating devices. Spacer links will not be so constrained, and theinclusion of such unconstrained links may be advantageous in manysituations where it is desirable to have portions of the actuatedmechanism be less rigid.

The terms “instrument” and “tool” are herein used interchangeably andrefer to devices that are usually handled by a user to accomplish aspecific purpose. For purposes of illustration only, link systems andarticulating mechanisms of the invention will be described in thecontext of use for the remote guidance, manipulation and/or actuation ofsurgical or diagnostic tools and instruments in remote accessed regionsof the body. As previously noted, other applications of the link systemsand articulating mechanisms besides surgical or diagnostic applicationsare also contemplated and will be apparent to one of skill in the art.Generally any such application will include any situation where it isdesirable to navigate an instrument or tool into a workspace that is noteasy to manually navigate by hand or that might otherwise present a riskor danger. These include, without limitation, industrial uses, such asfor the navigation of a tool, probe, sensor, etc. into a constrictedspace, or for precise manipulation of a tool remotely, for example, forthe assembly or repair of machinery. These can also include commercialand household situations where the targeted site for the application ofa tool or instrument is difficult to access. Other situations caninclude e.g. industrial applications where the work environment isdangerous to the user, for example, workspaces exposed to dangerouschemicals. Still other situations can include e.g. law enforcement ormilitary applications where the user may be at risk, such as deploymentof a tool or instrument into a dangerous or hostile location. Yet otheruses include applications where simply remote manipulation of complexgeometries is desirable. These include uses in recreation orentertainment, such as toys or games, e.g., for remote manipulations ofpuppets, dolls, figurines, and the like.

With reference to FIG. 1A, an embodiment of the invention is depictedwhich incorporates an articulating mechanism and link system accordingto the invention. As shown in FIG. 1A, needle driver 100 includes anarticulating mechanism 102 having a proximal link set 104 andcorresponding distal link set 106, separated by elongate shaft 112,which both maintains the proximal and distal link sets in a spaced apartrelationship and also provides a working shaft for advancing the needledriver. Needle driver tool 107 with grasping jaws 108, 109 is attachedto the distal end of distal link set 106 and is operationally connectedto ratchet handle 110, which is attached to the proximal end of proximallink set 104. Needle driver 100 as configured is suitable forlaparoscopic use. While this embodiment incorporates a needle drivertool, it will be readily appreciated that wide variety of surgical toolsand instruments can be operationally attached to the distal end,including but not limited to a Doppler flow meter, microphone,endoscope, light source, probe, retractor, dissector, stapler, clamp,grasper, scissors or cutter, or ablation or cauterizing elements, aswell as other tools or instruments for non-surgical applications, as hasbeen previously noted.

As depicted in greater detail in FIGS. 3A-5, proximal and distal linksets 104 and 106 include corresponding pairs of links, i.e., eachindividual link in proximal link set 104 is paired with an individuallink in distal link set 106 to form a series of discrete pairs. Distallink set 106 include links 122A, 124A, and 126A, while proximal link set104 include links 122B, 124B, and 126B. Link 122A and 122B, 124A and124B, and 126A and 126B are each discrete link pairs. The proximal links(122B, 124B, and 126B) are connected to the distal links (122A, 124A,and 126A) by sets of cables 134, 135 such that movement of proximallinks in proximal link set 104 causes a corresponding relative movementof distal link set 106. In particular, links 122A and 122B are connectedby cables 134, and links 124A and 124B are connected by cables 135, withlinks 126A and 126B affixed to elongate shaft 112. Links 122A and 122B,and links 124A and 124B, thus form active link pairs. Generallyspeaking, one or more sets of cables are used to connect active linkpairs of an articulating mechanism according to varying embodiments ofthe invention. As previously noted, each active link at one end of anarticulating mechanism is connected to its corresponding link at theother end by two or more cables that form a cable set. As noted,movement of one active link pair is controlled by its correspondingcable set and is independent of any other active link pair.

FIGS. 2A-D show a representation of a link set similar to link set 106as separated from device 100 and in greater detail. As can be seen,adjacent links 122 and 124 are separated by a bushing 130, and adjacentlinks 124 and 126 are separated by a bushing 132. As more clearly seenin FIG. 2C, each link is aligned along longitudinal axis X1 of the linkset with adjacent links 122 and 124 and adjacent links 124 and 126 eachhave opposing convex protrusions (123, 125, 127, 129) aligned along theaxis. Each bushing 130 and 132 has opposing concave depressions (131,133, 137, 139) for receiving the convex protrusions of links 122, 124,and 126. The links further include channels 138 that allow the passageof cable sets 134 and 135. Cable sets 134 and 135 are connected to links122 and 124, respectively. The cable channels are offset from thecentral axis of the links such that when a tension force is applied toone or more cables, the convex protrusions of the links 122, 124, and126 can rotate within the respective concave depressions of each bushing(130 and 132), thereby pivoting each link about a pivot point andallowing the link set as a whole to bend, as is shown more clearly inFIG. 2D. Each link and bushing also includes central channels 140 and141 respectively that are aligned with the central axis of each link orbushing. When assembled, these channels form a central lumen throughwhich an actuating cable (148) is passed for controlling and/oractuating the needle driver tool (107). The central channel generallyalso provide passage for additional cables, wires, fiberoptics or otherlike elements associated with any desired tool or instrument used inconjunction with the link system or articulating mechanism of theinvention. The central channels of bushings 130 and 132 terminate in theshape of a conical frustum 142, as shown. This allows the links andbushings to pivot relative one another without impinging the passage ofan actuating cable. The overall dimensions of the conical frustumportion generally will be commensurate with the degree of relativepivoting desired between the links and the bushings. While the provisionof a central channel is advantageous for the above reasons, it will beappreciated that links and bushings can also be provided without suchchannels, and that control of tool or instrument associated with thelink system or articulating mechanism of the invention can also beaccomplished by routing actuating cables and other like elements alongany radial location, including the periphery of the link system orarticulating mechanism.

Turning to FIGS. 3A-5, device 100 as noted includes elongate shaft 112disposed between proximal link sets 104 and distal links 106. The shaftis typically hollow and includes lumen 114 that accommodate both thecable sets 134 and 135 that connect the link pairs, as well as actuatingcable 148. The shaft lumen generally provides passage for additionalcables, wires, fiberoptics or other like elements associated with anydesired tool or instrument used in conjunction with the link system orarticulating mechanism of the invention.

Handle 110 of driver 100 is a conventional ratchet-style handle that isoperably linked to actuating cable 148. In particular, as shown in FIGS.3A, 3B and 5, handle 110 includes fixed arm 151 and pivoting arm 152,with arm 151 secured to proximal link 122B by collar 153 which engagesreciprocal hub 121B of link 122B. Pivoting arm 152 is pivotallyconnected to fixed arm 151 at pivot 150, and further includes pin 147,which is received and translatable in guide slot 149 of arm 151.Actuating cable 148 terminates at it proximal end at the distal end ofcable connector 146 which further receives pin 147 at its proximal end.When the handle 110 is actuated, arm 152 pivots around pivot point 150,thereby causing translational movement (i.e., rectraction) of the cableconnector 146 and actuating cable 148 toward the proximal end of thedevice.

As most clearly shown in FIG. 4, needle driver 107 is similarly securedto distal link 122A by collar 153 which engages reciprocal hub portion121A of link 122A. Jaws 108 and 109 extend distally with jaw 108 fixedand jaw 109 pivotally connected to jaw 108 at pivot 105. Cable connector154 attaches to jaw 108 at its distal end at pin 106, and the distal endof actuating cable 148 is secured to the proximal end of cable connector154. Spring 156 is disposed around cable 148 and between cable connector154 and distal link 122A, keeping the cable in tension and jaw 109 inthe open position, as shown. The needle driver is actuated by retractionof the central cable 148, which retracts connector 154 and compressesspring 156, causing pivotal movement of jaw 109 about pivot 105 into aclosed position against jaw 108.

In various embodiments of the invention, the link sets or link systemsare designed to have “neutral cable bias” based on the configuration ofeach link and bushing. When a link system bends due to an actuatingforce applied by a cable or cables along one side of the links, therelative tautness of cables passing through the links can be affected ina positive, negative or neutral manner. This effect, or bias, can alsobe referred to as “cable pull bias.” Link systems that create orincrease cable tension when the links are articulated are said to have“positive bias.” Alternatively, link systems that result in decreasedcable tension or slack when the links are articulated are referred to ashaving a “negative bias.” Link systems that minimize cable tension andcable slack are said to have “neutral bias.” Mechanisms that incorporatelink systems with a neutral cable bias can generally retain their shapeover a range of motion and resist counter forces applied against themechanism that would compromise shape accuracy, and thus are generallypreferred in most instances. However, depending on the application,negative or positive bias or effect can be advantageous. For example, incertain applications, negative cable bias, which introduces cable slack,may be desirable as it will decrease the rigidity of the articulatedlinks, and limit their resistance to counter forces deployed along thelinks. Certain examples where this could be desirable include navigationof the links through or around sensitive or fragile anatomicalstructures. In other applications, positive cable bias, which introducesincreased cable tension, may be desirable, as it will increase therigidity of the articulated links and further their resistance toapplied counter forces. Such tension can also provide resistance againstfurther bending or articulation of the links. Examples where this couldbe desirable include applications where it is important to guard againsttoo much bending or “overbending” of the link system.

Referring again to FIGS. 2A-2D, the particular configuration of thelinks and bushings in link set 106 achieves neutral cable bias.Important to achieving neutral cable bias in this embodiment is theprovision and location of the pivot points between eachlink-bushing-link assembly. Convex protrusions (123, 125, 127, 129) ofthe links 122, 124, and 126 are hemispherical, and concave depressions(131, 133, 137, 139) of the bushings 130 and 132 have a truncatedhemispherical shape. The hemispherical shapes of the convex protrusionsand concave depressions create pivot points P between adjacent links.The pivot points are located at the intersection of the central axis Xof the link set and a plane defined by the flat, non-protruding axialface 120 of each link 122, 124, and 126, and correlate with the axispoint around which the hemispherical convex protrusions arecircumscribed. This is more clearly seen with reference to FIGS. 2E and2F which show a link-bushing-link assembly similar in configuration tothose shown in FIGS. 2A-2D. Here again links 122 c and 124 c areseparated by bushing 130 c. Link 122 c and 124 c include hemisphericalprotrusions 123 c and 125 c, respectively, that are received bytruncated hemispherical depressions 131 c and 133 c of bushing 130 c.This configuration again creates pivot points P₁, P₂ between the twolinks that are located at the intersection of axis X and planes definedby axial faces 120 c of each link. The links otherwise have the sameoverall diameter, the corresponding cable channels have the same radiusor distance from the link center, and the same distance or gap betweenadjacent links, as maintained by the interposed bushings.

When the links are manipulated into a desired position or configuration,each link of a link-bushing-link assembly pivots about its respectivepivot point, such that any two adjacent links are pivoting toward oraway from one another about dual pivot points. Further, as a result ofsuch dual pivoting action for any given link, the distance a given cablechannel exit point moves towards its corresponding cable channel exitpoint on an adjacent link is equal to the distance an opposing cablechannel exit point on the opposite side of the link moves away from itscorresponding cable channel exit point on the adjacent link. Thecombined distance between the two respective sets of cable channel exitpoints, however, remains constant whether or not the links are pivotedwhich is important to maintaining neutral cable bias. Where suchcombined distances are not equal, an increase in cable slack or tensioncan occur. Particularly, where the combined distance between sets ofopposing channel exit points is greater when the links are pivoted orarticulated as compared to the combined distance in the straight,non-articulated position, cable tension can occur. Alternatively, wherethe combined distance between sets of opposing channel exit points islessened upon pivoting or articulation relative to a straight,non-articulated position, cable slack can occur.

This phenomena is illustrated more clearly with reference to FIGS.21A-23B, which show link assemblies (610, 640, 670) having neutral(FIGS. 21A-21B), negative (FIGS. 22A-22B), and positive (FIGS. 23A-23B)cable bias. Each link assembly (610, 640, 670) includes two adjacentlinks (622 and 624, 652 and 654, and 682 and 684) with a bushing (630,660, 690) interposed between the two links. Similar to the aboveembodiments, the links include convex protrusions (623, 625, 653, 655,683 and 685) that engage concave depressions (631, 633, 661, 663, 691,693) of the bushings. Link assembly 610 of FIGS. 21A and 21B isconfigured similarly to the assembly shown in FIGS. 2E and 2F, andachieves neutral cable bias. Protrusions 623 and 625 are hemisphericaland are received in depressions 631 and 633 that have a truncatedhemispherical shape. As with the assemblies of FIGS. 2A-2F, thisconfiguration also creates pivot points P₃ and P₄ located at theintersection of axis X₁ and the plane defined by the axial faces (620,621) of the two links (622, 624), which coincide with cable channel exitpoints (627, 629, 637, 639) of cable channels (626, 628, 636, 638). Asshown, exit points 627 and 629 of link 622 are on opposite sides of link622 and are aligned with exit points 637 and 639 on adjacent link 624when the assembly is in a straight, unbent position (FIG. 21A). In thisposition, the distance between exit points 627 and 637 and between 629and 639 is the same, and is represented as G1 in FIG. 21A. When theassembly is bent (FIG. 21B), the relative distances between thecorresponding exit points change, as represented by distances H1 and K1in FIG. 21B. However, with the pivot positions P₃ and P₄ located asdescribed above, the combined distance between opposing cable channelexit points remains the same as when the links are in the straight,unbent position. That is, G1+G1 is equivalent to H1+K1, which can berepresented by the formula G1+G1=H1+K1.

Link assembly 640 shown in FIGS. 22A-22B is designed to achieve negativecable bias, so as to increase cable slack upon articulation. The linksand bushing of this assembly are the same as in FIGS. 21A-21B with theexception that links 652 and 654 have hemispherical tipped protrusions653 and 655 that extend further from axial faces 650, 651 of links 652and 654. As a result, pivot points P₅ and P₆ are created that no longercoincide with cable channel exit points 657, 659, 667, and 669 of cablechannels 656, 658, 666, and 668, respectively. Instead, the pivot pointsare offset from the axial faces by a distance y₂ in a direction towardbushing 660. In this configuration, the combined distance betweenopposing cable channel exit points when pivoting occurs is not equal tothe combined distance between the respective cable channel exit pointswhen the links are in the straight, unbent position. That is, H2+K2 isnot equal to G2+G2, but instead is a lesser value which results in theintroduction of cable slack into the system. This can be represented bythe formula G2+G2=H2+K2+Δ2, with the degree of cable slack introducedinto the system correlating to the value Δ2.

Link assembly 670 (FIGS. 23A-23B) by contrast is designed to achievepositive cable bias which increases cable tension upon articulation.Again, the links and bushing of this assembly are the same as in FIGS.21A-21B, but here the exception is that links 682 and 684 have convexprotrusions 683 and 685 that are truncated hemispheres. This results inthe establishment of pivot points P₇ and P₈ that are offset by adistance y₃ from the planes defined by axial faces 680, 681 of thelinks, but this time in a direction away from bushing 690. Here again,then, the pivot points do not coincide with cable channel exit points687, 689, 697 and 699 of corresponding cable channels 686, 688, 696 and698. Again, the combined distance between opposing cable channel exitpoints when pivoting occurs is not equal to the combined distancebetween the respective cable channel exit points in the straight, unbentposition. Instead H3+K3 is greater than G3+G3, resulting in theintroduction of cable tension into the system. This can be expressed asG3+G3=H3+K3−Δ3. Here the degree of cable tension introduced into thesystem again correlates to the value of Δ3.

Neutral, negative, and positive cable bias can also be achieved in avariety of other link system conformations. By way of example and notlimitation, the variation shown in FIGS. 6A and 6B, shows an alternativeconfiguration of a link-bushing-link assembly that achieves similar dualpivoting and equidistant movement of cable channel exit points as doesthe FIGS. 2A-2D, 2E-2F, and 21A-21B links, and that also results inneutral cable bias. Link system 200 includes opposing adjacent links 202and 204 separated by bushing 210. Adjacent links 202 and 204 each haveopposing axially aligned hemispherical concave depressions (201, 203,205, 207). Bushing 210 has truncated hemispherical convex protrusions211, 213 for receiving the concave depressions 203 and 205 of each link202 and 204, respectively. The link system has two pivot points P₉ andP₁₀ located at the intersection of the central axis X₂ of the linksystem and the planes defined by axial faces 220 and 222, respectively,of links 202 and 204 and that intersect the bushing 210 and thatcorrelate with the axis points around which the truncated hemisphericalconvex protrusions of the bushing are circumscribed. The central channel214 of bushing 210 has a larger diameter than the central channels 216,218 of links 202 and 204, respectively, to allow for unimpeded passageof actuating cables, etc., when the links are pivoted, as can be seen inparticular by reference to FIG. 6B. By modifying the assembly tointroduce offset to the pivot point locations, positive or negative biascan be achieved.

Another link-bushing-link assembly is shown FIGS. 7A and 7B thatlikewise achieves neutral cable bias. The links of this system have bothconcave depressions and convex protrusions that engage a bushinginterposed between the links. The bushing likewise has correspondingconvex protrusions and concave depressions. This link-bushing-linkassembly likewise achieves similar dual pivoting and equidistantmovement of cable channel exit points as does the FIGS. 2A-2D links andFIGS. 6A and 6B links. Link system 250 includes opposing adjacent links252 and 254 separated by bushing 260. Link 252 has a hemisphericalconvex protrusion 256, and link 254 has an opposing hemisphericalconcave depression 258 that is axially aligned with convex protrusion256. Bushing 260 has a truncated hemispherical concave depression 262that receives convex protrusion 256 of link 252, and a truncatedhemispherical convex protrusion 264 that is received by concavedepression 258. The link system 250 has two pivot points P₁₁ and P₁₂located at the intersection of the central axis X₃ of the link systemand the plane defined by either the flat, non-concave and non-convexaxial face 270 of link 252, or the flat, non-concave and non-convexaxial face 272 of link 254 that intersects bushing 260. These pivotpoints further correlate with the axis points around which convexhemispherical protrusion of the link or the truncated hemisphericalconvex protrusions of the bushing are circumscribed. The central channel280 of bushing 260 has a larger diameter than the central channels 282,284 of links 252 and 254, respectively, to allow for unimpeded passageof actuating cables, etc., when the links are pivoted, as can be seen inparticular by reference to FIG. 7B. Again, by modifying the assembly tointroduce offset pivot point locations, positive or negative bias can beachieved.

While particular embodiments of bushings have been described as havingconvex protrusions and/or concave depressions that are engaged withconcave depressions and/or convex protrusions of corresponding links,bushings that are simply cylindrical and hollow with generally bluntends are likewise useful. Such bushings will function equally well whenengaged with the convex protrusions and/or concave depressions of thecorresponding links, provided the inner diameter of the bushing isslightly smaller than the diameter of the corresponding convexprotrusion, or alternatively the outer diameter of the bushing isslightly smaller than the corresponding concave depression, to allow forpivoting movement of the link relative to the bushing.

Consistent with the configurations and parameters otherwise discussedabove, the links and bushings in the link systems and articulatingmechanisms according to the invention may be of any size and shape, asthe purpose dictates. For surgical applications, their form usuallydepends on such factors as patient age, anatomy of the region ofinterest, intended application, and surgeon preference. As noted, linksand bushings are generally cylindrical, and may include channels forpassage of the cables that connect links to other links or components ofa device, as well as additional cables, wires, fiberoptics or other likeelements associated with a desired tool or instrument used inconjunction with the link system. The channel diameters are usuallyslightly larger than the cable diameters, creating a slip fit. Further,the links may also include one or more channels for receiving elementsof attachable surgical instruments or diagnostic tools or for passage ofcables that actuate them. As noted, such channels can be located alongthe center or the periphery or at any radial location of the links orbushings. The links may typically have a diameter from about 0.5 mm toabout 15 mm or more depending on the application. Bushings tend to haverelatively comparable sizes to links, and frequently have a smallerdiameter. For endoscopic applications, representative link diameters mayrange from about 2 mm to about 3 mm for small endoscopic instruments,about 5 mm to about 7 mm for mid-sized endoscopic instruments, and about10 mm to about 15 mm for large endoscopic instruments. For catheterapplications, the diameter may range from about 1 mm to about 5 mm. Theoverall length of the links and bushings will vary, usually depending onthe bend radius desired between links.

For surgical applications, the links or bushings or other components ofthe mechanism or device into which the links or bushings areincorporated may be made from any biocompatible material including, butnot limited to, stainless steel; titanium; tantalum; and any of theiralloys; and polymers, e.g., polyethylene or copolymers thereof,polyethylene terephthalate or copolymers thereof, nylon, silicone,polyurethanes, fluoropolymers, poly (vinylchloride); and combinationsthereof. A lubricious coating may be placed on the links or bushings orother components if desired to facilitate advancement of the linksystem. The lubricious coating may include hydrophilic polymers such aspolyvinylpyrrolidone, fluoropolymers such as tetrafluoroethylene, orsilicones. A radioopaque marker may also be included on one or morelinks or bushings to indicate the location of the articulating mechanismor device upon radiographic imaging. Usually, the marker will bedetected by fluoroscopy.

Although the many link systems that have been illustrated in theaccompanying figures have a certain number of links and bushings, thisis solely for the illustrative purpose of indicating the relationship ofthe individual mechanism or link and bushing components to one another.Any number of links and bushings may be employed, depending on suchfactors as the intended use and desired length and range of movement ofthe articulating mechanism.

As noted, cables may be used to actuate the link systems of theinvention. In such embodiments, one or more links are connected to itscorresponding link or segment at the distal end by two or more cables.Each cable set may be made up of at least two cables. As noted, movementof one link is controlled by its corresponding cable set and isindependent of any other link. In certain variations, for example, acable set will include three cables. By using a set of three cables toconnect to a link, the link can be manipulated or moved in three degreesof freedom (i.e., up/down motion, left/right motion, and rotational or“rolling” motion), independently of any other links. By combining aplurality of links, multiple degrees of freedom are achieved, allowingthe link system to be shaped into various complex configurations. Forexample, the distal link set 106 shown in FIG. 2A has a total of threelinks (122, 124, 126) with two links (122, 124) independently connectedby sets of cables (134, 135), for possible motion in six degrees offreedom. Such multiple degrees of freedom are not available in typicalconventional mechanisms where only a single set of cables is employed tomanipulate the links.

Cable diameters vary according to the application, and may range fromabout 0.15 mm to about 3 mm. For catheter applications, a representativediameter may range from about 0.15 mm to about 0.75 mm. For endoscopicapplications, a representative diameter may range from about 0.5 mm toabout 3 mm.

Cable flexibility may be varied, for instance, by the type and weave ofcable materials or by physical or chemical treatments. Usually, cablestiffness or flexibility will be modified according to that required bythe intended application of the articulating mechanism. The cables maybe individual or multi-stranded wires made from material, including butnot limited to biocompatible materials such as nickel-titanium alloy,stainless steel or any of its alloys, superelastic alloys, carbonfibers, polymers, e.g., poly (vinylchloride), polyoxyethylene,polyethylene terephthalate and other polyesters, polyolefin,polypropylene, and copolymers thereof; nylon; silk; and combinationsthereof, or other suitable materials known in the art.

The cables may be affixed to the links according to ways known in theart, such as by using an adhesive or by brazing, soldering, welding, andthe like, including methods described in pending and co-owned U.S.application Ser. No. 10/444,769, incorporated herein by reference in itsentirety. In the embodiment depicted in FIG. 5, cable 134 is secured tolink 122B by set screws 143.

Spacer links, i.e., links not connected by discrete sets of cables, mayalso be included in the link systems and articulating mechanisms of theinvention. These links act as passive links that are not independentlyactuatable, but do allow for pass through of cable sets to neighboringactive links. Spacer links can be desirable for providing additionallength in a link system or articulating mechanism. In addition theinclusion of spacer links at one end of the mechanism allows for theproportional scaling of movement or motion of the corresponding otherend. For example, the inclusion of spacer links at the proximal end ofan articulating mechanism in which distal and proximal pairs of linksare connected would require a more exaggerated movement by the user atthe proximal end to achieve the desired motion at the distal end. Thisis advantageous in situations where fine, delicate controlled movementswere desired, such as, for example, situations where there is a riskthat a user may not possess the necessary dexterity to perform thedesired procedure absent such proportional scaling of the distal endmovement or motion. Alternatively, spacer links can be provided on thedistal end, in which case the degree of distal end movements would beproportionally greater than those of the proximal end, which may also bedesirable for particular applications. In addition to the above,proportional scaling of movement or motion can also be accomplished byincreasing or decreasing the radius or distance that the cable channelsare located from the center axis, as further described.

Turning to the embodiment of FIGS. 1A and 1B, the configuration of theproximal and distal links is such that movement of proximal link set 104causes amplified movement in distal link set 106. With particularreference to FIGS. 4 and 5, it can be seen that proximal links 122B,124B and 126B are generally larger than their distal counterparts 122A,124A and 126B. More importantly, the radius or distance that the cablechannels (138B) are located from the center axis of the correspondinglinks is greater for proximal links 122B, 124B and 126B relative totheir distal link counterparts (138A). As a result of this difference,the given link pairs when manipulated exhibit reciprocal movement thatis proportional to this difference. For any two link pairs, thedifference can be expressed in terms of the resulting pivot angle thatresults when the links are manipulated relative to their unpivotedstate. Thus, for any given link pair L₁ and L₂ having differing cablechannel location radii of R₁ and R₂, respectively, and where R₂>R₁, whenL₁ is pivoted to an angle of A₁, corresponding link L₂ will have aresulting pivot angle A₂=A₁×sin (R₁/R₂). An increase or decrease ofcable channel location radii can therefore proportionally increase ordecrease the bend angle of corresponding proximal and distal linksystems. This can have important ergonomic applications, including insurgical application where a smaller angle of flex at the useroperating, proximal end can result in a greater angle of flex or bend atthe distal end, allowing for exaggerated or increased movement of thedistal end to deploy and/or actuate surgical tools or instruments. Thiscan be seen with particular reference to FIG. 1B, which shows the linksets 104 and 106 of device 100 in a bent configuration. The angle ofmovement of needle driver 107 at the end of distal link set 106 relativeto elongate shaft 112 is approximately 90 degrees, and proportionallygreater than the angle of handle 110 at the proximal end of proximallink set 104 relative to the shaft, which as shown is approximately 45degrees.

In the embodiment shown in FIGS. 1 and 3-6, handle 110 is affixed to theproximal end of proximal link set 104. In this configuration, the handleitself can be used to manipulate the proximal links thereby resulting incorresponding manipulation of the distal links. Thus the handle itselfcan be used to manually manipulate and steer the distal end needledriver. In an alternative embodiment depicted in FIG. 8, needle driver700 includes handle 710 which is directly affixed to the proximal end ofelongate shaft 712. Proximal link set 704 is operably connected todistal link set 706 as before, but associated link cables are routedsuch that link set 704 emerges from the handle itself with thedistal-most link of the link set being secured to the handle. In thisconfiguration, the handle can manipulate or direct the elongate shaft.The proximal link set then is separately manipulated in order to steerdistal end needle driver tool 707, similar to a joystick. This“joystick” configuration can provide increased control by the user incertain orientations or uses.

The linking systems, articulating mechanisms, and devices incorporatingsuch systems or mechanisms may also include a locking mechanism. Whenactivated, the locking mechanism prevents one or more links or pairs oflinks from moving. In one aspect, the locking mechanism is configured toreceive the cables (or other like actuating elements) that connect toand manipulate the links and, when activated, restrict cable (or otherlike actuating element) movement thereby restricting and lockingcorresponding connected link pairs. In certain variations, the lockingmechanism includes moveable locking members and a fixed contact member,such that movement of the moveable locking members brings the cables (orother like actuating elements) into contact with the fixed contactmember, impeding further movement of the cables (or other like actuatingelements) and thereby also impeding movement of the links. The lockingmechanism described are compatible with the links and link systemsdisclosed herein as well as other link systems, including thosedescribed e.g. in pending and co-owned U.S. application Ser. No.10/444,769, incorporated herein by reference in its entirety, as well asother known link systems.

FIGS. 9-12 show an embodiment of one such locking mechanism. Withparticular reference to FIG. 11A-11B, locking mechanism 300 includes anaxially aligned fixed collar 302 and an axially aligned moveable collar304 within housing 305. The inner surface of fixed collar 302 and theouter surface of moveable collar 304 are tapered such that moveablecollar 304 can be partially received within fixed collar 302 asdepicted. Pin 312 extends from moveable collar 304 through slot 314 inhousing 305. Lever 310 is pivotally connected to housing 305 at pivot316, with cam 318 in contact with pin 312. Cables 309 and 308 arealigned along the longitudinal axis of the mechanism. The cable arefurther received through fixed collar 302 and then deployed around theperimeter moveable collar 304. In the unlocked position, as shown inFIGS. 9B, 11B and 12B, lever 310 is in the upright position,approximately perpendicular to axis of the mechanism. In this position,there is sufficient clearance between the two collars to allow thecables to freely translate through the mechanism with minimal frictionalcontact between fixed collar 302 and movable collars 304, as is shownmost clearly in FIG. 12B.

In the locked position, as depicted in FIGS. 9A-11A, lever 310 ispivoted downward until approximately parallel to the central axis of thelocking mechanism. This movement causes cam 318 to engage and translatepin 312 and thus collar 304 toward collar 302. When the lever in thelocked position, the pin engages detent 319, maintaining the lever inthe locked position. As a result of such movement collar 304 towardcollar 302, the cables come into frictional contact with the collars andare in essence pinched between the two collars, thereby frictionallyimpeding further movement of the cables and thus also impeding movementof links connected to the cable.

FIGS. 13-18 show another embodiment of a locking mechanism according tothe invention. In this embodiment, locking mechanism 400 includeshousing 402 with channels that receive cables. As will be appreciated,the housing can be incorporated into the shaft portion or elsewherealong an articulating mechanism. Alternatively the shaft portion itselfcan form the housing. Slider 410 surrounds housing 402 and is moveablerelative to the housing in an axial direction. Housing 402 also includesa central channel 408 running along the central axis of the cylinder.The slider moves in the direction of the central axis to activate thelocking mechanism, as is further described. FIGS. 17A and 18A show topand cross-sectional views, respectively, of the axial slider mechanismin the unlocked position. With reference to FIG. 18A, the housingincludes two locking channels 414 and 416 disposed at differentpositions with respect to the central axis of housing 402. Buttonmembers 418 and 424 are disposed in locking channels 414 and 416,respectively. Each button member includes a head (421, 427), spring(420, 426) and a cable contact element (422, 428). With reference tobutton member 418, cable contact element 422 is positioned in channel414 perpendicular to the central axis and in proximity to cable 432 asit passes through channel 436. Spring 426 has sufficient expansive forceto maintain contact element 422 in light contact with the cable and head421 in contact with the interior of slider 410, while still allowingcable 432 to pass freely through channel 436 with minimum resistance.Button member 424 is similarly situated in channel 416 and similarlyoriented relative to cable 434 as it passes through channel 438.

As seen most clearly in FIGS. 18A-18C, slider 410 includes areas wherethe inner diameter of the slider is larger such that there is a gapbetween the slider and housing 402, as well as areas where innerdiameter of the slider is smaller such that there is only a smallclearance between the slider and the housing. These areas are alignedlinearly to coincide with the locking channels. When the axial slidermechanism 400 is in the fully unlocked position (FIGS. 17A and 18A), theslider 410 is positioned such that the gap areas are aligned with bothlocking channels 414 and 416. In the fully unlocked position, neitherbutton member exerts sufficient force against the respective associatedcable to frictionally impede movement of the cables. The cables (432,434) are thus free to translate in their respective through-channels(436, 438), resulting in corresponding movement of any attached linksystem (not shown).

The locking mechanism 400 is activated by moving the slider 410 in thealong the axis of the locking mechanism 400. FIGS. 17B and 18B showmechanism 400 in a partially locked position, where cable 434 is locked,but cable 432 is still free to translate. With reference to FIG. 18B, itcan be seen that slider 410 has now been positioned such that at area ofminimal clearance now coincides with locking channel 416. As a result,the slider exerts increased radial force against head 427 of buttonmember 424 along locking channel 416 that overcomes the expansive forceof spring 426 such that cable contact member 428 is pressed againstcable 434 with increased force and into frictional contact with theinside wall of channel 438. Further translational movement of cable 434is impeded, as thus is any further movement of a link or links (notshown) connected to cable 434. In this same configuration however,slider 410 continues to have a gap area coinciding with locking channel414, such that cable 432 remains free to translate withinthrough-channel 436, and thus a link or links (not shown) associatedwith cable 432 remain moveable. The net result is that translationalmovement of cable 434 is frictionally impeded, but movement of cable 432is unimpeded, thereby partially locking an associated link system (notshown).

FIGS. 17C and 18C show locking mechanism 400 in the fully lockedposition. With reference to FIG. 18C, the slider 410 is positioned withareas of minimal clearance coinciding with both locking channels 414 and416, such that both cable contact elements (422, 428) button members(418, 424) are pressed against their respective cables (432, 434)bringing the cables into frictional contact with the inner walls oftheir respective through channels (436, 438), thereby frictionallyimpeding translational movement of both cables and any associated links.As can be appreciated from this embodiment, different links or pairs oflinks connected by separate sets of cables can have locking channelsassociated with each set that are oriented radially about a specifiedposition along the housing axis. As the slider is moved axially relativeto the housing, these links or pairs of links can be sequentially lockedor unlocked. The ability to sequentially lock or unlock the connectedlinks or link pairs can be advantageous, for example, in situations wereit is desirable to lock portions of the link systems in place whileother portions remain free for further steering, navigation, direction,or actuation of a distal tool or instrument. Further, not all cables ofa link set need be restrained for effective locking of connected linkpairs. For example, for cable sets having three cables, only two need berestrained for effective locking.

In further embodiment of a locking mechanism according to the inventionis depicted in FIGS. 19-20. Locking mechanism 500 includes cylindricalhousing 502 surrounded by co-axial locking rings 510 and 512. Lockingrings 510 and 512 are rotatable around housing 502, and function similarto slider 410 in the embodiment of FIGS. 13-18. When locking rings 510and 512 are rotated to specific positions, one or more cables that arereceived through housing 502 are prevented from moving. Again, thehousing itself can be integrated into the shaft portion of anarticulating mechanism, or elsewhere along the mechanism, or the shaftportion itself can form the housing.

FIGS. 20A and 20B show locking mechanism 500 in unlocked (FIG. 20A) andlocked (FIG. 20B) conformations with respect to cables 519, 521, 523.Housing 502 is surrounded by coaxial locking ring 510. The interior oflocking ring 510 and the exterior perimeter of cylinder does not have auniform matching diameter but rather have sections with tapered gapsinterspersed by sections with only minimal clearance between the two.Cylinder 502 includes three locking channels 518, 520, and 522 disposedat various positions radially about the cylinder 502. Each lockingchannel (518, 520, 522) is associated with a cable through channel thatreceives an associated cable (519, 521, 523). It will be appreciatedthat the remaining depicted cables will be associated with locking ringsand channels in different axial locations along the housing. The buttonmembers are similarly configured and in their respective channels as arethose of the FIGS. 13-18 embodiment, with each button member (526, 534,540) having a head (527, 535, 541), spring (528, 532, 538), and cablecontact member (529, 533, 539). With further reference to FIG. 20A, whenthe locking mechanism is in the unlocked configuration, the locking ring510 is positioned so that each of the button members (526, 534, 540) isaligned with a gapped area, such that none of the buttons is depressedwith sufficient force to move the associated cables (519, 521, 523) intofrictional contact with the inner walls of their respective throughchannels so as to impede cable movement. Thus, in this unlocked positionthe cables (519, 521, 523) are free to translate through cylinder 502.

FIG. 20B shows the mechanism moved into a locked configuration byrotating locking ring 510 around cylinder 502. When the locking ring 510is rotated to the locked configuration, each of the buttons (526, 534,540) now coincides with an area of minimal clearance between lockingring 510 and cylinder 502. Much like in the embodiment of FIGS. 13-19,this similarly results in each of the buttons (526, 534, 540) beingdepressed into the locking channels with sufficient force to overcomeassociated spring members (528, 532, 538) and push their associatedcable contact members (529, 533, 539) radially against their associatedcables (519, 521, 523), bringing the associated cables into frictionalcontact with the inner wall of their associated through channels. Inthis manner, cables (519, 521, 523) are frictionally impeded fromfurther translational movement through cylinder 502, thereby locking thecables and any links connected to the cables in place. As can beappreciated from this embodiment, different links or pairs of linksconnected by separate sets of cables can again have locking channelsassociated with each set that are oriented radially about a specifiedposition along the cylinder that is associated with a single lockingring. Each of these links or link pairs can thus be independently lockedor unlocked. The ability to independently lock or unlock the connectedlinks or link pairs can have many advantages, including as previouslymentioned situations were it is desirable to lock portions of the linksystems in place while other portions remain free for further steering,navigation, direction, or actuation of a distal tool or instrument.

Locking mechanisms may be of any size and shape, as the purposedictates, but their size and shape is typically similar to that of anyassociated link system, articulating mechanism, or device incorporatingsuch systems or articulating mechanisms. Like the link systemsthemselves, the locking mechanisms are generally but need not becylindrical, and may include channels for passage of the cables thatconnect the locking mechanism to other components of a device, as wellas additional cables, wires, fiberoptics or other like elementsassociated with a desired tool or instrument used in conjunction withthe locking mechanism. In embodiments of the locking mechanism thatinclude cables, cable channel diameters are usually slightly larger thanthe cable diameters, creating a slip fit. Further, the lockingmechanisms may also include one or more channels for receiving elementsof attachable surgical instruments or diagnostic tools or for passage ofcables that actuate them.

In some embodiments, a locking mechanism may be disposed on one end of alinking system or articulating mechanism. In other embodiments, thelocking mechanism may be disposed at any position at the proximal ordistal end of the surgical instrument. Although the many lockingmechanisms that have been illustrated in the accompanying figures havecertain configurations number components, this is solely for theillustrative purpose of indicating the relationship of the components toone another. Any number of components may be employed, depending on suchfactors as the intended use of the locking mechanism.

The invention also contemplates kits for providing various linkingsystems, articulating mechanisms, locking mechanisms, and associatedaccessories. For example, kits containing linking systems andarticulating mechanisms having different lengths, different segmentdiameters, and/or different types of tools or instruments may beprovided. The kits may optionally include different types of lockingmechanisms. The kits may be further be tailored for specificapplications. For example, kits for surgical applications can beconfigured for, e.g., endoscopy, retraction, or catheter placement,and/or for particular patient populations, e.g., pediatric or adult.

1-16. (canceled)
 17. An articulating medical tool comprising: a proximallink system including a pair of proximal articulating links; a distallink system including a pair of distal articulating links; and anactuating element coupled to the pair of proximal articulating links andto the pair of distal articulating links, wherein an actuating forceapplied to the actuating element causes the a first bend angle to formbetween the proximal articulating links and causes a second bend angleto form between the pair of distal articulating links, wherein the firstand second bend angles are different.
 18. The articulating medical toolof claim 17 wherein the actuating element is one in a set of radiallyspaced actuating elements coupled to the pair of proximal articulatinglinks to the pair of distal articulating links
 19. The articulatingmedical tool of claim 18 wherein a central axis extends through theproximal and distal link systems and the radially spaced actuatingelement extend a first radial distance from the central axis wherecoupled to the pair of proximal articulating links and extend a secondradial distance from the central axis where coupled to the pair ofdistal articulating links, wherein the first radial distance varies fromthe second radial distance.
 20. The articulating medical tool of claim17 wherein each of the proximal articulating links has a first lengthand each of the distal articulating links has a second length, whereinthe first length varies from the second length.
 21. The articulatingmedical tool of claim 17 wherein the proximal link system includes aproximal bushing interposed between the pair of proximal articulatinglinks and the distal link system includes a distal bushing interposedbetween the pair of distal articulating links
 22. The articulatingmedical tool of claim 21 wherein the proximal bushing has a first lengthand the distal bushing has a second length, wherein the first lengthvaries from the second length.
 23. The articulating medical tool ofclaim 21 wherein each of the articulating links of at least one of thepairs of articulating links includes a pair of axially alignedhemispherical protrusions.
 24. The articulating medical tool of claim 21wherein each of the articulating links of at least one of the pairs ofarticulating links includes a pair of axially aligned hemisphericaldepressions.
 25. The articulating medical tool of claim 21 wherein eachof the articulating links of at least one of the pairs of articulatinglinks include a hemispherical protrusion axially aligned with ahemispherical depression.
 26. An articulating medical tool comprising: aproximal link system including a pair of proximal articulating links,each of the links including an actuator channel; a distal link systemincluding a pair of distal articulating links, each of the linksincluding an actuator channel; and an actuating element coupled to thepair of proximal articulating links through the proximal articulatinglink actuator channels and to the pair of distal articulating linksthrough the distal articulating link actuator channels, wherein anactuating force applied to the actuating element causes a first actuatortension to form between the proximal articulating links and causes asecond actuator tension to form between the pair of distal articulatinglinks, wherein the first and second actuator tensions are different. 27.The articulating medical tool of claim 26 wherein in the absence of anapplied actuating force, a first distance extends between the actuatorchannels of the proximal articulating links and a second distanceextends between the actuator channels of the distal articulating links,wherein the first distance varies from the second distance.
 28. Thearticulating medical tool of claim 27 wherein the first distance isgreater than the second distance.
 29. The articulating medical tool ofclaim 27 wherein the first distance is less than the second distance.30. The articulating medical tool of claim 26 wherein a proximal bushingextends between the proximal articulating links and a distal bushingextends between the distal articulating links
 31. The articulatingmedical tool of claim 26 wherein the proximal bushing has a first lengthand the distal bushing has a second length and wherein the first lengthvaries from the second length.